构架三种常用疲劳强度校核方法对比研究

Study on the Differences between the Three Common Fatigue Strength Analysis Methods for Bogie Frame

对比分析转向架构架三种常用疲劳强度校核方法的差异。分别采用铁路标准中规定的载荷谱、多刚体系统动力学仿真(Multiple rigid body system dynamic simulation,MRBSDS)技术获取的载荷谱和线路动应力测试应力谱等三种方法对某型地铁拖车转向架构架进行疲劳强度校核。通过准静态叠加法将载荷谱转换为应力谱,准静态叠加法中给出应力响应因子(Stress response factor,SRF)的定义,方便载荷谱和应力谱之间的转换。对比方法是将三种方法获取的应力谱线性外推至100万km进行疲劳等效应力计算。计算结果表明,与线路试验相比,利用标准中规定的载荷谱进行疲劳强度校核略偏保守,MRBSDS方法获取的载荷谱无法准确预测疲劳寿命。应力谱频域分析发现,MRBSDS方法计算疲劳载荷谱应朝采用真实且含有高频信号的线路谱和刚柔耦合模型方向发展。

The differences between the three common fatigue strength analysis methods for bogie frame are studied. Comparison of the three main methods, the normative loading spectrum from the railway standard, the loading spectrum from multiple rigid body system dynamics simulation（MRBSDS） and the stress spectrum from running test, is conducted on one trailer bogie frame under the same precondition. During the analysis, the quasi-static superposition method is used to convert the loading spectrum to stress spectrum. Among the quasi-static superposition method, stress response factor（SRF） is defined, which is useful for the conversion between loading spectrum and stress spectrum. Equivalent stress of one million kilometers is used to contrast the three methods. Though comparative analysis, fatigue analysis results based on the railway standard are conservative and results from the MRBSDS method could not predict the fatigue life accurately. From the frequency domain comparative analysis, MRBSDS method should adopt the real line spectrum which contains high-frequency components and consider rigid-flexible coupled model to create loading spectrum.